The use of various fluorochemical compositions on fibers and fibrous substrates, such as textiles, paper and leather, to impart oil- and water-repellency is known. See for example, Banks, Ed., Organofluorine Chemicals and Their Industrial Applications, Ellis Horwood Ltd., Chichester, England, 1979, pp. 226-234.
Certain fluorinated compounds containing urethane bonds are known. A common synthetic route for forming such compounds containing urethane bonds uses isocyanate compounds as starting materials. The use of blocking or masking agents to `protect` the unreacted isocyanate moieties is also known.
U.S. Pat. No. 3,398,182 teaches fluorocarbon compounds which contain a highly fluorinated oleophobic and hydrophobic terminal portion and a different nonfluorinated oleophilic portion linked together by a urethane radical obtained by reacting together an isocyanate and a highly fluorinated organic compound containing an active hydrogen. Surfaces coated with such fluorocarbon compounds are oleophobic and hydrophobic and the coating is durable, resisting removal by abrasion.
U.S. Pat. No. 4,788,287 and U.S. Pat. No. 4,792,354 disclose a water and oil repellent compound having at least two terminal segments and an intermediate segment connecting the terminal segments and having a molecular weight of from 800 to 20,000, each terminal segment containing at least one polyfluoroalkyl group connected by a --CONH-- linking group, the intermediate segment being a urethane oligomer containing at least two --CONH-- linking groups in one molecule, and said terminal segments and intermediate segment being connected by a --CONH-- linking group. The urethane oligomer of U.S. Pat. No. 4,792,354 further contains a hydrophilic molecular chain.
U.S. Pat. Nos. 5,276,175 and 5,453,540 teach fluorochemical compositions comprising fluorinated compounds, wherein the fluorinated compound comprises a fluorochemical oligomeric portion, an organic moiety, and a group that can impart soft hand, stain release, water repellency, or a durable property when the compound is applied to a fibrous substrate, wherein the fluorochemical oligomeric portion is bonded to the organic moiety through an isocyanate-derived linking group.
U.S. Pat. Nos. 5,276,175 and 5,453,540 disclose fluorochemical compositions comprising fluorinated compounds, wherein the fluorinated compound comprises a fluorochemical oligomeric portion, an organic moiety, and a group that can impart soft hand, stain release, water-repellency, or a durable property when the compound is applied to a fibrous substrate, wherein the fluorochemical oligomeric portion is bonded to the organic moieties through an isocyanate-derived linking group. These fluorochemical compounds, however, are not polyurethanes in the sense of the present invention, because the patents teach that, if a reagent containing two or more functional groups reactive to an isocyanate is used to prepare the compound, at least one of the functional groups will have a substantially lesser degree of reactivity with isocyanates than the others and the less reactive group will generally remain unreacted; see U.S. Patent No. 5,276,175, column 22, lines 27-35, and U.S. Pat. No. 5,453,540, column 20, lines 58-66.
U.S. Pat. No. 5,491,261 discloses di-, tri- and poly-perfluoroalkyl-substituted alcohols and acids and derivatives thereof which are prepared from perfluoroalkyl iodides and di-, tri- or polyallyl alcohols or acids. They can be reacted with isocyanates, epoxy compounds, anhydrides, acids or acid derivatives to prepare a great variety of oil- and water-repellent compositions.
The inclusion of silicone moieties in treatments with fluorochemicals which provide oil- and water-repellency is known to improve the feel or `hand` of the treated substrates.
U.S. Pat. No. 5,260,400 relates to silicone and perfluoroalkyl group containing telomers useful as coatings on glass, paper, wood, leather and especially textiles.
U.S. Pat. No. 4,098,742 teaches polyurethanes which contain at least one segment derived from a perfluoroalkyl-substituted diol and at least one segment derived from a reactive-hydrogen-containing polysiloxane, which are synthesized by co-polycondensation with an organic diisocyanate.
U.S. Pat. No. 5,258,458 discloses a composition for treating fibrous substrates such as textiles to provide oil and water repellency. The composition comprises a) a terpolymer comprising randomly distributed i) units containing a fluoroaliphatic group, Rf, ii) fluorine-free hydrocarbon units, and iii) units containing silicone and b) a fluorine-containing polymer having isocyanate derived linking groups and blocked isocyanate moieties.
European Patent Publication 0 383 310 A2 teaches a water and oil repellent containing a copolymer of a first vinyl monomer having a perfluoroalkyl group, a second vinyl monomer having a polyorganosiloxane chain and a third vinyl monomer having an isocyanate group or blocked isocyanate group as essential components. As an alternative, a water and oil repellent contains a copolymer of a first vinyl monomer having a polyorganosiloxane chain and a second vinyl monomer having an isocyanate group or blocked isocyanate group, in combination with a water and oil repellent compound having a perfluoroalkyl group.
U.S. Pat. No. 5,019,428 teaches that modified polyurethanes containing perfluoroaliphatic groups which are obtained by reacting oligo(poly)urethanes containing free hydroxyl or isocyanate groups and perfluoroaliphatic groups with di/polyfunctional polysiloxanes at elevated temperatures with conversion of all the reactive groups of the urethane are used for the oil- and water-repellent finishing of fiber materials.
Environmental and safety concerns nowadays require the majority of all repellent treatment applications to be made from aqueous formulations in place of organic solvents. Practically all of the known compositions which can be applied from an aqueous emulsion require a heat-curing step after application and drying.
U.S. Pat. No. 5,344,903 teaches that lower homologue perfluoroalkylethyl (meth)acrylates copolymerized with vinylidene chiloride and alkyl (meth)acrylates; optionally with N-methylolacrylamide, hydroxyalkyl (meth)acrylates, and/or akloxy(meth)acrylates impart high levels of water-, alcohol- and oil-repellency to fabrics under mild conditions.
U.S. Pat. No. 5,350,795 discloses fluorochemical compositions for treating textile fibers and fabrics to impart oil and water repellency without thermal treatment. The compositions comprise an aqueous, substantially organic solvent free, solution or dispersion of (a) a fluorochemical acrylate copolymer comprised of a fluorinated acrylate monomer, polyalkylene glycol acrylate or methacrylate, and polyalkylene glycol diacrylate or dimethacrylate; and (b) a polyalkoxylated polyurethane having pendant perfluoroalkyl groups comprised of an aliphatic or aromatic tri- or higher order isocyanate, a fluorinated alcohol, amine or mercaptan, and a poly(oxyalkylene)diol or dithiol.
Although water- and oil-repellent treating agents are readily available, it is very difficult to combine high initial oil- and water-repellency with excellent laundering and dry-clean durability. Furthermore, many high performance fluorochemicals have a tendency to impart a harsh feeling to the treated fabric. Although silicones can be applied to overcome this problem, silicones are usually not compatible with the fluorochemicals and therefore, the treated substrates typically will show a decrease in water and especially oil repellency.
Although existing patents claim durable repellent compositions, resistant to laundering and dry cleaning, they virtually all require a heat treatment after home launderings in order to regain the repellent properties. In known textile treatments, especially the dynamic water repellency is completely lost without heat treatment.